Psychopathology typically has its onset during the adolescent years. In addition, 25 percent of all adolescents are considered overweight or obese, and 70 percent of obese adolescents will become obese adults. Both the development of psychopathology and the development of obesity are public health concerns, yet very little is known about the relationship between obesity and psychopathology, particularly in adolescents. Research to date, including cross-sectional and longitudinal studies, has not demonstrated consistent relationships between psychopathology and the development of obesity. Less is known about the possibility of the converse relationship; obesity as a risk factor for the development of psychopathology. Since there are escalating rates of obesity, and obesity has a negative effect on psychosocial functioning during this critical developmental period, obesity could be contributing to the development of psychopathology in adolescents. Only one study has evaluated obesity as a risk factor for psychopathology by examining the risk of chronic obesity in the development of psychopathology. However, that study was limited by a small sample size, and the lack of diversity in the sample. In addition, there is very little information regarding possible mediators in this relationship. Thus, the overall aim of the proposed project is to analyze two high-quality, racially diverse 4-year, longitudinal datasets to evaluate obesity as a risk factor for the development of depression, anxiety and high levels of substance use. These analyses will examine the longitudinal relationships between obesity and the incidence of psychopathology, the role of chronic obesity as a risk factor for psychopathology, and possible psychosocial mediators in the relationship between obesity and psychopathology. The results of these analyses will be instrumental in designing prospective studies to evaluate the relationships between obesity and psychopathology. The overall purpose of these analyses is to evaluate the weight-related etiological risk factors for psychopathology, and to identify intervention opportunities to prevent the development of psychopathology in adolescents. [unreadable] [unreadable]